文档图象的版面分析一基于数学形态学的方法

提出了基于Hough变换的结构元素构造方法(HTSEC)以及基于数学形态学的分割方法(MMS)，即首先将灰度文档图象利用半色调技术转换为二值图象，利用Hough变换动态构造结构元素，然后利用数学形态学方法对版面进行划分并将其分为文字区、图形区和图象区．     

一种直线提取的新方法

直线提取是版面分析中的一个重要过程。该文提出了基于Hough变换的结构元素构造方法(HTSEC)以及基于数学形态学的直线提取方法(MMLE)，即首先将灰度文档图像利用半色调技术转换为二值图像，利用Hough变换检测直线倾斜角度以动态构造结构元素，然后利用数学形态学方法提取文档图像中的直线。     

利用动态结构元素提取直线

研究了灰度文档图像中提取直线的方法．首先将灰度文档图像利用半色调技术转换为二值图像，进行倾斜矫正后利用Hough变换动态构造结构元素(HTSEC)；然后根据这些结构元素，利用数学形态学中的击中／击不中变换提取文档图像中的直线(MMLE)。     

数学形态学的图象分割算法

图象分割在图象分析、机器视觉、目标识别中都将直接影响到后续的理解和识别工作。本文着重讨论了基于数学形态学变换的图象分割算法，提出了基于图象最大内切圆的数学形态学形状描述图象分割算法和基于目标最小闭包结构元素的数学形态学形状描述图象分割算法。     

基于数学形态学的二维条码识别

边缘模糊会导致二维条码识别率下降。本文提出了一种基于Hough变换和数学形态学相结合的二维条码识别算法,得到了清晰的条码边缘,从而有效地降低了边缘模糊对条码识别的影响。文中选取PDF417二维条码为应用对象,利用Hough变换和数学形态学对二维条码进行识别,选择合适的结构元素。实验结果表明,基于数学形态学对二维条码的识别算法能够更有效地识别条码边界,显著地提高了条码的识别率。     

一种基于数学形态学的图象多尺度分析方法的研究

提出了一种基于数学形态学的图象多尺度分析方法。利用数学形态学在描述图象形态特征方面的优势，通过改变结构基元的尺度，提取图象在不同尺度下的有用信息。该方法将基于二值图象的集合处理的数学形态学方法，推广至基于灰度形态处理的数学形态学方法，提出了广义的数学形态学形态变换算子，拓宽了数学形态学理论在图象处理领域的应用范围。本文给出了人造的实验图象和实际的景物图象的实验结果，提取出图象在不同尺度下各个层次的目标和特征，证明该方法的有效性。     

基于数学形态学的商标图象边缘提取

介绍一种全新的基于数学形态学的商标图象边缘提取方法,根据商标图象边缘与内部区域结构形态的差异,通过与之相匹配的结构元素,运用数学形态学的方法对商标图象边缘进行提取。     

基于数学形态学和Hough变换的复杂形态线状地物提取方法

为改善以Hough变换提取遥感影像中弯弧线状地物的准确性,提出了一种新算法M&H (Morphology and Hough),它将Hough变换、数学形态学、非线性拟合等方法串行递进使用,以实现复杂形态线状地物自动提取和直接生成道路矢量图的目标。经适量实例的Matlab仿真测试,证明了M&H的递进噪声去除法优于单次数学形态学降噪法,对含弯弧道路的提取性能也优于标准Hough变换。精度检验结果表明:M&H方法比常规Hough变换提取道路的欠提取率下降了约18.9%。     

关于彩色图象处理的形态学算子研究

彩色形态变换是数学形态学从灰度图象到彩色图象的推广,基于ＲＧＢ（ｒｅｄ－ｇｒｅｅｎ－ｂｌｕｅ）彩色坐标系统,提出了彩色形态变换的理论,并讨论了它们的性质,进而建立了彩色形态变换与灰度形态学的联系,彩色形态变换作为一种数学形态学方法在彩色空间的延拓,可有效地应用于彩色图象处理、图象编码和目标形状特征提取等。     

基于数学形态学和Hough变换的车牌定位算法

针对复杂环境下的车牌定位率较低的问题,提出了一种基于数学形态学和Hough变换检测车牌区域的方法。首先,对车牌图像进行图像预处理,然后,利用数学形态学的高帽变换突出车牌字符区域,并对图像进行边缘检测和连通区域分析;最后,结合Hough变换和车牌的先验知识实现车牌的精确定位。实验结果表明,针对不同复杂背景下采集到的车辆图像,该算法具有很强的鲁棒性,准确率达97.3%,能够满足现代智能交通系统对车牌定位准确性和实时性的要求。     

数字图像中基于多尺度几何分析的圆检测算法

特征检测是图像处理和模式识别中非常重要的问题,其检测效果直接影响模式识别和分类。基于多尺度几何分析（MGA）的思想,提出了一种圆检测方法―圆特征域上奇异点算法。该算法首先将圆特征曲线变换到圆特征域上,然后在圆特征域上进行小波分析以找出奇异点,奇异点坐标即为待检圆的坐标。该方法克服了Hough变换对灰度图像圆检测需要考虑灰度阈值或梯度的限制,可直接对二值图像或灰度图像进行检测。最后分析、比较了该算法与Hough算法的不同。     

局部PCA参数约束的Hough多椭圆分层检测算法

针对随机Hough变换(RHT)在复杂图像中检测圆及椭圆时随机采样所造成的大量无效采样、无效累积以及运算时间长等问题,提出基于局部PCA感兴趣参数约束Hough多椭圆分层检测思路。首先利用边缘检测算子获得边缘信息并去除边缘交叉点,在边缘图像中标记并提取出满足一定长度的连续曲线段;其次利用线段PCA方向分析确定是否属于有效曲线段;然后,对所有感兴趣曲线段按照标记顺序依次利用椭圆拟合办法初步得到感兴趣椭圆粗略参数,根据拟合结果进而模糊约束Hough变换参数搜索范围,得到精确椭圆参数;最后利用检测结果更新图像空间,删除已经检测到的椭圆,依次进行,直到所有椭圆检测完毕。实验结果表明,该算法在计算、存储消耗上均大大减少。     

Detecting line segments in an image – a new implementation for Hough Transform

The conventional Hough Transform is a technique for detecting line segments in an image. The conventional Hough Transform transforms image points into lines in the parameter space. If there are collinear image points, the lines transformed from the points intersect at a point in the parameter space. Determining the intersection is generally carried out through the “voting method”, which partitions the parameter space into squared meshes. A problem with the voting method involves determining the resolution required for partitioning the parameter space. In this paper, we present a solution to this problem. We propose to transform an image point into a belt, whose width is a function of the width of a line in the image. We then determine the intersection of numerous belts to detect a line segment. An iterated algorithm based the transformation for detecting line segments is presented in this paper.     

快速霍夫变换算法

二值图像的直线检测过程中,标准霍夫变换算法的计算量为O（N^3)。该文提出一种快速霍夫变换算法,其计算量仅为O（N^2log2N)。该快速算法可以并行实现;处理器阵列规模为O（N^2)时,计算量为O（log2N)。文中还分析得到快速算法的误差上界,并提出一种改进的快速霍夫变换算法以获得更高的计算精度。最后,给出算法的数值算例。理论分析及数值算例都表明,该文的快速霍夫变换算法在直线检测过程中有着更高的计算效率,并且具有良好的计算精度。     

Point-to-line mappings as Hough transforms

In 1962 [US Patent 3069654], Hough used a linear point-to-line mapping (PTLM) to detect large sets of collinear points in an image, by mapping the points into concurrent lines and detecting peaks where many lines intersect. In 1972, Duda and Hart [Commun. ACM 15 (1972) 11] pointed out that Hough's method is not practical, because the peaks need not lie in a bounded region. They (and others after them) therefore developed methods of detecting sets of collinear points using nonlinear point-to-curve mappings that map collinear points into concurrent curves whose intersections do lie in a bounded range. In this paper we show that any PTLM that maps collinear points into concurrent lines must be linear, and that no such PTLM can map all the sets of collinear points in an image into peaks that lie in a bounded region; thus Duda and Hart's objection applies to any PTLM-based Hough transform.     

Recovering 3D motion of multiple objects using adaptive Houghtransform

We present a method to determine 3D motion and structure of multiple objects from two perspective views, using adaptive Hough transform. In our method, segmentation is determined based on a 3D rigidity constraint. Instead of searching candidate solutions over the entire five-dimensional translation and rotation parameter space, we only examine the two-dimensional translation space. We divide the input image into overlapping patches, and, for each sample of the translation space, we compute the rotation parameters of patches using least-squares fit. Every patch votes for a sample in the five-dimensional parameter space. For a patch containing multiple motions, we use a redescending M-estimator to compute rotation parameters of a dominant motion within the patch. To reduce computational and storage burdens of standard multidimensional Hough transform, we use adaptive Hough transform to iteratively refine the relevant parameter space in a “coarse-to-fine” fashion. Our method can robustly recover 3D motion parameters, reject outliers of the flow estimates, and deal with multiple moving objects present in the scene. Applications of the proposed method to both synthetic and real image sequences are demonstrated with promising results     

用于形状检测的极标编码多分辨率Hough变换

本文提出一种利用Hough变换作形状检测的方法,称为极标编码多分辨率Hough变 换,它将模板和图象都用极坐标表示为一维序列,这不但简化了Hough变换的映射运算,而 且借此可以构成图象空间和参数空间对等的多分辨率描述,使检测可由低分辨率向高分辨率 以一种类似树搜索的方式高效地实现.文中给出了实验结果.     

A shape-based voting algorithm for pedestrian detection and tracking

This paper presents the MOUGH (mixture of uniform and Gaussian Hough) Transform for shape-based object detection and tracking. We show that the edgels of a rigid object at a given orientation are approximately distributed according to a Gaussian mixture model (GMMs). A variant of the generalized Hough transform is proposed, voting using GMMs and optimized via Expectation-Maximization, that is capable of searching images for a mildly-deformable shape, based on a training dataset of (possibly noisy) images with only crude estimates of scale and centroid of the object in each image. Further modifications are proposed to optimize the algorithm for tracking. The method is able to locate and track objects reliably even against complex backgrounds such as dense moving foliage, and with a moving camera. Experimental results indicate that the algorithm is superior to previously published variants of the Hough transform and to active shape models in tracking pedestrians from a side view.     

基于Hough变换的建筑边缘特征检测的研究及其改进

Hough变换是对二值图像进行直线检测的有效方法,介绍了Hough变换直线检测对房屋边缘特征检测方法及实验结果,并根据其存在的缺点提出了检测矩形的Hough变换的改进算法.